In the present description and in the claims, with the expression “rim or tired wheel of or for motorcycles” it is intended a rim or a tired wheel having a central through hole of smaller diameter than the central through hole of a rim or tired wheel for automobiles, even if this is a rim or tired wheel that is not for motorcycles.
As is known, tire mounting-demounting machines for mounting-demounting tires on-from rims for automobiles are equipped with a support table that can be fixed or drivable in rotation; in such case, it also drives in rotation a rim or tired wheel loaded thereon. The wheel-carrier rotatable table usually has a threaded central hole of standard 40 mm diameter and is equipped with jaws for engaging and locking a rim (bare or tired) arranged thereon. Once the jaws are tightened against the rim, a threaded pin or bar is inserted in a loose manner; after having crossed through the central hole of the rim, such pin/bar is screwed into the threaded hole of the wheel-carrier table. The threaded pin or bar has a length much greater than the thickness or width than the rim, so that the threaded pin or bar projects from the rim even after its screwing in the wheel-carrier table. A cone is screwed on the projecting part of the threaded pin or bar, until such cone is brought into forced abutment against rim; the rim will thus be tightened between the wheel-carrier table and the cone, so that it is made integral in rotation with the wheel-carrier table.
Motorcycle wheels have their rim provided with central through hole having a standard diameter of about 18 mm, such that a normal tire mounting-demounting machine for automobile wheels is not adapted to be used for motorcycle wheels.
It would be desirable to be able to arrange a tire mounting-demounting machine with universal use, i. e. usable for handling rims and tired wheels of automobiles as well as motorcycles.
Tire mounting-demounting machines have also been proposed lacking wheel-carrier rotatable table and equipped with multiple expansion arms for the engagement of the rim, angularly mounted spaced around a rotatable shaft, as taught by the patent application EP-0 499 825 (for example). Each expansion arm bears at its head a respective pad for engaging against an edge of a rim, usually the internal edge.
As will be understood, with the expansion arms during the locking-releasing operations, there is the risk of impacting or in any case interfering with projecting portions of a motorcycle wheel, whose rim is integral or which is in any case made integral with a brake disc (front wheel of the motorcycle) or a chain sprocket (rear wheel). In addition, as specified above with regard to the size of the threaded pin or bar, one would in any case not be able to lock a motorcycle wheel against the expansion arms.
EP-0 001 855, DE-16 80 348, WO-2009/015920, US-2005/199349, and FR-1 567 801 disclose respectively prior art tools for supporting and locking a rim or tired wheel in position on a tire mounting-demounting machine.